An air tanker crashed while working to control a 1,200-acre (480-hectare) wildfire burning near Rocky Mountain National Park, killing the two people on board, aviation officials said.

The plane went down about a mile (1.5 kilometers) north of the blaze, which has forced residents to flee about 120 homes in the northern Colorado foothills, fire information officer Martha Moran said.

Witnesses said the tanker — a PB4Y model — broke into pieces before plummeting to the ground about 45 miles (72 kilometers) northwest of Denver.

"There was a bright flash of flame on the left wing. The wing came off and after that he spiraled down. It was just a collective gasp by everybody, 'Oh my God, it went down,'" said Roy Safstrom, who was taking pictures of the wildfire.